A Conversation with Ralph Cicerone

Ralph Cicerone

By Audra Wolfe

The 2006 Ullyot Lecturer, Ralph Cicerone, has received many accolades for his work in atmospheric chemistry, climate change, and related public policy. As president of the National Academy of Science, Cicerone has often testified before Congress; he previously chaired an NAS study on climate change at the request of the White House. Cicerone spoke with Chemical Heritage’s editor as a preview to his lecture in November, 2006.

ED: Why is it important for the public to understand climate change?

RC: Let’s take an earlier issue from atmospheric chemistry, the degradation of the stratospheric ozone layer, as an example. Dealing with the problem required individuals to understand the mechanisms and the reality of the effects, both to encourage businesses to develop technological solutions and to provide the basis for government and individual actions. People were being asked to believe that tiny aerosol spray cans could have a planetary impact, to believe in scientific instruments and calculations without being able to see anything. Eventually, the data were credible enough that our chemical companies decided to deal with the issue by creating, through true synthetic chemistry, a better line of products that contain less chlorine and molecules that degrade more quickly in the lower atmosphere.

Climate change is an even more difficult situation because there are so many variables: it’s not just temperature, but it’s sea level, rain patterns, maximum temperatures, minimum temperatures, and ocean currents, and the frequency of extreme events like floods and droughts all mixed with the changing length of a growing season. We’re dealing with something very complicated, yet there are still issues of personal choice, personal purchasing patterns and lifestyle, incentives to business, and the need for governmental actions at all scales, including international. You just can’t get those things done without having people involved.

ED: It sounds like both the underlying problems and many of the solutions are chemical problems.

RC: Chemistry is just everywhere in these issues. Even though carbon dioxide emissions are the biggest single problem, there are other significant greenhouse gases. For example, the chlorofluorocarbons that were in refrigerants and aerosol spray products have been replaced with products designed to be more compatible with natural breakdown processes in the atmosphere. Some greenhouse gases are extraordinarily long-lived: carbon tetrafluoride and sulfur hexafluoride have survival times of 50,000 years or more in the atmosphere. To understand the role of those two greenhouse gases requires some pretty specialized chemistry, in this case atmospheric chemistry and laboratory spectroscopy.

ED: Is there a tipping point in climate change?

RC: We used to assume that planetary climate change would happen gradually and that previous changes over geological history had been gradual, but as the record has been refined—as measurement techniques have been developed to measure dust layers and the isotopic content of individual species and classes of compounds—the time resolution has improved so that now there really is evidence of sudden change throughout climate history. These kinds of observations are going into the view that there may indeed be a point of no return where the climate will be destabilized if we keep forcing it the way we’re doing. The idea of a tipping point is based on actual observations and better understandings of the mechanisms involved.

ED: Climate change is unquestionably controversial. Where do the controversies
lie?

RC: While the science is very tricky, most of the disagreements are really about what to do about climate change and involve the lag times in the system. For example, if we want to ward off a certain level of change 10, 30, or 40 years from now, what do we have to do now? One kind of uncertainty arises because the future depends partially upon human behavior: how many people will we have, what will our energy sources be, and how efficient will they be? What will be our standard of living and level of consumption? And while there is uncertainty in prediction due to the physical and biological science of climate, the change itself is becoming clearer than people had expected it to be at this point.

ED: What do you see as the scientist’s role in setting policy?

RC: Scientists are going to have to have a big role in setting policy to help to define options. . . . Just as a realistic scenario, how much can we limit carbon dioxide emissions right now if we were to focus only on energy efficiency? Many more people can be brought into the discussion about energy efficiency than just those people who are concerned about climate change—people who are interested in saving money, who are interested in creating new products for world markets, who are trying to minimize our dependence on foreign oil—but we need scientists and engineers who can work through exactly how much benefit can be had from just energy efficiency and which new energy technologies are feasible. The role for scientists and engineers in all of this is just going to keep growing. Not that they have to make all of the decisions—that’s not what I’m saying —but we really have to be part of it.